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Biomedical subjects

H Eberhard

Publications and source records attributed to H Eberhard.

5 recordsLinked to original sources
PubMed1998

Treatment of Class II, Division 2 in the late growth period.

The "Deckbiss" with skeletal Class II jaw relationship sometimes presents a considerable therapeutic problem, particularly in the late growth period (DP3U), as regards the coordination of dental and skeletal treatment objectives. An effective treatment approach was demonstrated: a modified Herbst appliance used simultaneously with fixed appliances in the maxilla. The sample comprised 12 male (14.0 +/- 0.9 years old) and 10 female (12.3 +/- 0.4 years old) patients. Correction of the distal occlusion was achieved in all patients by means of the Herbst appliance, which was removed after an average time period of 6.4 +/- 0.2 months. In the mandible the multibracket appliances were then immediately inserted, and Class II elastics were used for retention. Maximum anchorage was required in the maxilla as well as in the mandible. Complete diagnostic records were made at the beginning of the treatment as well as 6 and 12 months later, in order to document skeletal and dental changes. A dental and skeletal Class I relationship was achieved in all cases. A significant improvement was recorded in the vertical jaw base relationship; this was still stable after a period of 12 months. In the dental area in particular, a so-called high-pull headgear effect (intrusion and distalization 16, 26) and intrusion of teeth 34, 44 were registered. Only a minor protrusion of the mandibular incisors was observed. Reinforcement of the bands reduced the failure rate significantly. The Herbst appliance does not represent a standard treatment for Class II. Its indication range is limited.

Adolescent↗
PubMed1997

Evaluation of the bond strength of different bracket-bonding systems to bovine enamel.

In an experimental study the bond strength of stainless steel, ceramic and plastic brackets to bovine enamel was investigated by tensile testing. The brackets were cemented to the enamel using a conventional two-paste orthodontic bonding resin, a light-cured, fluoride-releasing adhesive, a no-mix-orthodontic bonding resin and a light-curing glass ionomer cement. For evaluation of the experimental data the Weibull analysis was applied. The highest values for the Weibull modulus (m) and the 10 per cent probability of failure (sigma.10) were found in the tested plastic brackets (Dentaurum Edgewise plastic bracket and Spirit bracket) using a no-mix orthodontic bonding resin (System 1). However, the tensile stresses for the 90 per cent probability of failure (sigma.90) were over 10 MPa and carried the danger of enamel fracture. Bracket bonding with glass ionomer cement cannot be recommended because of the low bond strength values for the 10 per cent probability of failure (sigma.10). The most favourable bracket-bonding system concerning the Weibull modulus (m), the 10 and 90 per cent probabilities of failure (sigma.10 and sigma.90) and aesthetics was the ceramic bracket with the silane-treated base (Allure III) using the light-cured, fluoride-releasing orthodontic bonding resin (Sequence). Bond fracture occurred predominantly between bracket and orthodontic bonding resin, with two exceptions. Concerning the ceramic bracket with the silane-treated base (Allure III) using the light-cured glass ionomer cement (Photac Fil), there was no preferential site of failure. Regarding the ceramic bracket with the silane-treated base (Allure III) using the light-cured, fluoride-releasing orthodontic bonding resin (Sequence), bracket fracture was seen more often than bond separation between bracket and enamel. When the bond failure was located at the enamel-orthodontic bonding resin interface enamel prisms could be identified on the adhesive site by scanning electron microscopy.

Adhesives↗
PubMed1997

Compomers--a new bracket bonding generation in orthodontics?

Compomers are a new class of materials. With the compomer Dyract Ortho., specifically for bracket bonding, and with Prime & Bond 2.0, a one-component primer for enamel and dentin, DeTrey/Dentsply has developed alternative new materials. The aim of this in vitro study was to test the tensile bonding strength of these materials with different kinds of brackets. Twelve test groups, each with 30 prepared bovine incisors, were formed. Two primers, Prime & Bond 2.0 and PSA, were used. 50% of all teeth were first etched will 36% phosphoric acid. Three types of brackets--metal, ceramic and silan ceramic--were bonded with the compomer Dyract Ortho. For 90 teeth forming a control group, the composite Concise was used. When conditioning the enamel with 36% phosphoric acid, the compomer Dyract Ortho showed a similar tensile bonding strength to the composite Concise. This was not the case if metal brackets were used. Metal brackets had significantly less tensile bonding strength (p < 0.001). The interface of the compomer with the bracket was the main failure site. There was insufficient retention between the compomer and the foil mesh of the bracket base because of the strong consistency of the compomer. Without enamel etching, Dyract Ortho produced an acceptable result only in combination with the primer Prime & Bond 2.0 and silan ceramic brackets. As insufficient data are available to date, the use of compomers in clinical practice cannot yet be recommended.

Animals↗
PubMed1994

[An in-vitro study of the bonding and fracture pattern of light-hardening, fluoride-releasing bonding materials in metal brackets].

Three hundred bovine incisors, which were divided into 6 groups of 50 teeth each, were used in this study. Two types of metal brackets, 1 with a conventional foil mesh base and the other with a photo-etched Micro-Loc base, were adhered to the teeth with 3 different bonding agents, namely, Sequence, a fluoride-releasing, light-activated composite, Photac-Fil, a light-hardened glass ionomer cement, and, in the control group, Concise, a 2-component composite which hardens chemically. A universal testing machine was employed to test tensile bonding strength and the site of failure was visually determined and analyzed. The study showed that Sequence can be considered as a qualitatively equal alternative to Concise. Both composites demonstrate equal tensile bonding strength. The use of Photac-Fil, the light-hardened glass ionomer bonding agent, cannot be recommended. It possesses significantly less tensile bonding strength than the other 2 bonding agents. Sequence and Concise, which showed better results with the brackets with conventional foil mesh base than with the brackets with photo-etched Micro-Loc base, had no significant differences in their failure sites. The interface of the composite with the bracket was the main failure site. Both composites demonstrated a significantly reduced rate of failure at the interface of the composite with the enamel, when they were used with the brackets with the Micro-Loc base. This differed from the failure site of Photac-Fil, when the photo-etched base was used. With Photac-Fil the main site of failure came at the interface of the enamel with this glass ionomer cement.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗